Rotor and rotary electric machine

ABSTRACT

A rotor includes an axially extending in an axial direction, a rotor core including a central hole through which the shaft passes and accommodation holes radially outside the central hole, and magnets accommodated in the accommodation holes. The accommodation holes include a pair of accommodation holes extends in a direction away from each other in a circumferential direction from a radially inside toward a radially outside when viewed in the axial direction. The magnets include a pair of magnets accommodated in the pair of accommodation holes. The rotor core includes through-holes made at intervals in the circumferential direction, and is configured by laminating plates. The through-holes are located radially outside the central hole and radially inside the accommodation hole. The stacked plates are fixed to each other by a caulking portion in which a portion of the plate is caulked.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 toJapanese Patent Application No. 2020-195511, filed on Nov. 25, 2020, theentire contents of which are hereby incorporated herein by reference.

1. FIELD OF THE INVENTION

The present disclosure relates to a rotor and a rotary electric machine.

2. BACKGROUND

There is known a rotary electric machine including a rotor including aplurality of plates in which rotor cores are stacked, the plates beingfixed to each other by a caulking portion. For example, conventionally,a rotary electric machine having a structure in which two permanentmagnets are held in a pair of magnet holding portions separated fromeach other from a rotor center side toward a rotor outer peripheral sideas such the rotary electric machine is known.

In the conventional rotor of the rotary electric machine, when thecaulking portion is simply provided, a magnetic flux flowing in therotor core is obstructed by the caulking portion, and there is a fearthat magnetic efficiency of the rotor is reduced.

SUMMARY

An example embodiment of a rotor of the present disclosure is rotatableabout a center axis extending in an axial direction, the rotor includesa shaft extending in the axial direction, a rotor core including acentral hole through which the shaft passes and accommodation holeslocated radially outside the central hole, the rotor core being fixed tothe shaft, and magnets accommodated in the accommodation holes. Theaccommodation holes include a pair of accommodation holes arranged atintervals in a circumferential direction. The pair of accommodationholes extends in a direction away from each other in the circumferentialdirection from a radially inside toward a radially outside when viewedin the axial direction. The magnets includes a pair of magnetsaccommodated in the pair of accommodation holes. The pair of magnetsextends in the direction away from each other in the circumferentialdirection from the radially inside toward the radially outside whenviewed in the axial direction. The rotor core includes through-holesmade at intervals in the circumferential direction, and is defined bylaminating of plates in the axial direction. The through-holes arelocated radially outside the central hole and radially inside theaccommodation hole. The stacked plates are fixed to each other by acaulking portion in which a portion of the plates is caulked. Thecaulking portion is located in a first region between the through-holesadjacent to each other in the circumferential direction.

An example embodiment of a rotary electric machine of the presentdisclosure includes the rotor and a stator located radially outside therotor.

The above and other elements, features, steps, characteristics andadvantages of the present disclosure will become more apparent from thefollowing detailed description of the example embodiments with referenceto the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view illustrating a rotary electric machineaccording to an example embodiment of the present disclosure.

FIG. 2 is a sectional view illustrating a portion of the rotary electricmachine of an example embodiment of the present disclosure, and is asectional view taken along a line II-II in FIG. 1.

FIG. 3 is a sectional view illustrating a magnetic pole of an exampleembodiment of the present disclosure.

FIG. 4 is a sectional view illustrating a portion of a rotor core of anexample embodiment of the present disclosure.

FIG. 5 is a sectional view illustrating a first gap and a second gap ofan example embodiment of the present disclosure.

FIG. 6 is a sectional view illustrating a flow of a magnetic flux in therotor of an example embodiment of the present disclosure.

FIG. 7 is a sectional view illustrating a caulking portion according toa modification of an example embodiment of the present disclosure.

DETAILED DESCRIPTION

A Z-axis direction appropriately illustrated in each drawing is avertical direction in which a positive side is an “upper side” while anegative side is a “lower side”. A center axis J appropriatelyillustrated in each drawing is a virtual line that is parallel to theZ-axis direction and extends in the vertical direction. In the followingdescription, an axial direction of the center axis J, namely, adirection parallel to the vertical direction is simply referred to as an“axial direction”, a radial direction centered on the center axis J issimply referred to as a “radial direction”, and a circumferentialdirection centered on the center axis J is simply referred to as a“circumferential direction”. An arrow θ appropriately illustrated ineach drawing indicates the circumferential direction. The arrow θ isdirected in a clockwise direction around the center axis J when viewedfrom above. In the following description, a side on which the arrow θ isdirected in the circumferential direction with a certain object as areference, namely, a side traveling in the clockwise direction as viewedfrom an upper side is referred to as “one side in the circumferentialdirection”, and a side opposite to the side on which the arrow θ isdirected in the circumferential direction with the certain object as thereference, namely, a side traveling in the counterclockwise direction asviewed from the upper side is referred to as “the other side in thecircumferential direction”.

The vertical direction, the upper side, and the lower side are merelynames for describing a relative positional relationship between therespective units, and an actual layout relationship and the like may beother than the layout relationship indicated by these names.

As illustrated in FIG. 1, a rotary electric machine 1 according to anexample embodiment is an inner rotor type rotary electric machine. Inthe example embodiment, the rotary electric machine 1 is a motor. Therotary electric machine 1 includes a housing 2, a rotor 10, a stator 60,a bearing holder 4, and bearings 5 a, 5 b. The housing 2 accommodatesthe rotor 10, the stator 60, the bearing holder 4, the bearings 5 a, 5b. A bottom portion of the housing 2 holds the bearing 5 b. The bearingholder 4 holds the bearing 5 a. For example, each of the bearings 5 a, 5b is a ball bearing.

The stator 60 faces the rotor 10 with a gap interposed therebetween. Thestator 60 is disposed radially outside the rotor 10. The stator 60includes a stator core 61, an insulator 64, and a plurality of coils 65.The stator core 61 includes an annular core-back 62 and a plurality ofteeth 63 that protrude radially inside from the core-back 62. Theplurality of coils 65 are installed to the plurality of teeth 63 withthe insulator 64 interposed therebetween.

The rotor 10 is capable of rotating about a center axis J extending inthe axial direction. As illustrated in FIG. 2, the rotor 10 includes ashaft 11, a rotor core 20, and a plurality of magnets 40. The shaft 11has a columnar shape that extends in the axial direction while beingcentered on the center axis J. The shaft 11 include a recess 11 arecessed in the radial direction. The recess 11 a is recessed radiallyinside from an outer peripheral surface of the shaft 11. In the exampleembodiment, two recesses 11 a are provided across the center axis J inthe radial direction. Although not illustrated, for example, the recess11 a extends in the axial direction. As illustrated in FIG. 1, the shaft11 is rotatably supported about the center axis J by bearings 5 a, 5 b.

The rotor core 20 is a magnetic material. The rotor core 20 is fixed tothe outer peripheral surface of the shaft 11. The rotor core 20 includesa central hole 21 axially penetrating the rotor core 20. As illustratedin FIG. 2, the central hole 21 has a substantially circular shapecentered on the center axis J when viewed in the axial direction. Theshaft 11 passes through the central hole 21. The central hole 21includes a protrusion 22 protruding in the radial direction. Theprotrusion 22 protrudes radially inside from the inner peripheralsurface of the central hole 21. In the example embodiment, twoprotrusions 22 are provided across the center axis J in the radialdirection. The two protrusions 22 are fitted into the two recesses 11 a.The protrusion 22 is hooked on the recess 11 a in the circumferentialdirection. As a result, relative rotation between the shaft 11 and therotor core 20 in the circumferential direction is prevented. Forexample, the protrusion 22 is press-fitted into the recess 11 a.

The rotor core 20 includes a plurality of accommodation holes 30 locatedradially outside the central hole 21. For example, the plurality ofaccommodation holes 30 penetrates the rotor core in the axial direction.A plurality of magnets 40 are accommodated in the plurality ofaccommodation holes 30, respectively. A method for fixing the magnet 40in the accommodation hole 30 is not particularly limited. In the exampleembodiment, the magnet 40 is fixed in the accommodation hole 30 byfilling a portion other than a portion where the magnet 40 is located inthe accommodation hole 30 with resin. The plurality of accommodationholes 30 include a pair of accommodation holes 31 a, 31 b.

The type of the plurality of magnets 40 is not particularly limited. Forexample, the magnet 40 may be a neodymium magnet or a ferrite magnet.The plurality of magnets 40 include a pair of magnets 41 a, 41 b.

In the example embodiment, a plurality of the pair of accommodationholes 31 a, 31 b and a plurality of the pair of magnets 41 a, 41 b areprovided at intervals in the circumferential direction. For example,eight each of the pair of accommodation holes 31 a, 31 b and the pair ofmagnets 41 a, 41 b are provided.

The rotor 10 is provided with a plurality of magnetic poles 70 eachincluding the pair of accommodation holes 31 a, 31 b and the pair ofmagnets 41 a, 41 b along the circumferential direction. For example,eight magnetic poles 70 are provided. For example, the plurality ofmagnetic poles 70 are arranged at equal intervals over an entirecircumference along the circumferential direction. The plurality ofmagnetic poles 70 includes a plurality of magnetic poles 70N in whichthe magnetic pole on the outer peripheral surface of the rotor core 20is an N pole and a plurality of magnetic poles 70S in which the magneticpole on the outer peripheral surface of the rotor core 20 is an S pole.For example, four magnetic poles 70N and four magnetic poles 70S areprovided. The four magnetic poles 70N and the four magnetic poles 70Sare alternately arranged along the circumferential direction. Theconfiguration of each magnetic pole 70 is similar to each other exceptthat the magnetic poles on the outer peripheral surface of the rotorcore 20 are different and that the circumferential positions aredifferent.

As illustrated in FIG. 3, in the magnetic pole 70, the pair ofaccommodation holes 31 a, 31 b is disposed at intervals in thecircumferential direction. For example, the accommodation hole 31 a islocated on one side (+θ side) in the circumferential direction of theaccommodation hole 31 b. For example, the accommodation holes 31 a, 31 bextend substantially linearly in a direction inclined obliquely withrespect to the radial direction when viewed in the axial direction. Thepair of accommodation holes 31 a, 31 b extends in directions away fromeach other in the circumferential direction from the radially insidetoward the radially outside when viewed in the axial direction. That is,a circumferential distance between the accommodation hole 31 a and theaccommodation hole 31 b increases from the radially inside toward theradially outside. For example, the accommodation hole 31 a is located onone side in the circumferential direction from the radially insidetoward the radially outside. For example, the accommodation hole 31 b islocated on the other side (−θ side) in the circumferential directionfrom the radially inside toward the radially outside. For example, thepair of accommodation holes 31 a, 31 b is disposed along a V-shapeexpanding in the circumferential direction toward the radially outsidewhen viewed in the axial direction. Radially outer ends of theaccommodation holes 31 a, 31 b are located at a radially outer edge ofthe rotor core 20.

For example, the accommodation hole 31 a and the accommodation hole 31 bare disposed with a magnetic pole center line CL1 in FIG. 3 interposedtherebetween in the circumferential direction when viewed in the axialdirection. The magnetic pole center line CL1 is a virtual line thatpasses through the circumferential center of the magnetic pole 70 andthe center axis J and extends in the radial direction. For example, theaccommodation hole 31 a and the accommodation hole 31 b are arrangedline-symmetrically with respect to the magnetic pole center line CL1when viewed in the axial direction.

Hereinafter, the description of the accommodation hole 31 b may beomitted for the same configuration as the accommodation hole 31 a exceptfor the line symmetry with respect to the magnetic pole center line CL1.In the following description, in each magnetic pole, the sideapproaching the magnetic pole center line CL1 in the circumferentialdirection with respect to a certain object is referred to as a“circumferential inside”.

The accommodation hole 31 a includes a main body 31 c, an inner end 31d, and an outer end 31 e. The main body 31 c extends linearly in thedirection in which the accommodation hole 31 a extends when viewed inthe axial direction. For example, the main body 31 c has a rectangularshape when viewed in the axial direction. The inner end 31 d isconnected to a radially inside end of the main body 31 c. The inner end31 d is a radially inside end of the accommodation hole 31 a. The outerend 31 e is connected to the radially outer end of the main body 31 c.The outer end 31 e is a radially outer end of the accommodation hole 31a. The accommodation hole 31 b includes a main body 31 f, an inner end31 g, and an outer end 31 h.

The pair of magnets 41 a, 41 b is accommodated in the pair ofaccommodation holes 31 a, 31 b, respectively. The magnet 41 a isaccommodated in the accommodation hole 31 a. The magnet 41 b isaccommodated in the accommodation hole 31 b. For example, the pair ofmagnets 41 a, 41 b has a rectangular shape when viewed in the axialdirection. Although not illustrated, for example, the magnets 41 a, 41 bhave a rectangular parallelepiped shape. Although not illustrated, forexample, the magnets 41 a, 41 b are provided over the entire axialdirection in the accommodation holes 31 a, 31 b. The pair of magnets 41a, 41 b is disposed at intervals in the circumferential direction. Forexample, the magnet 41 a is located on one side (+θ side) in thecircumferential direction of the magnet 41 b.

The magnet 41 a extends along the accommodation hole 31 a when viewed inthe axial direction. The magnet 41 b extends along the accommodationhole 31 b when viewed in the axial direction. For example, the magnets41 a, 41 b extend substantially linearly in a direction inclinedobliquely with respect to the radial direction when viewed in the axialdirection. The pair of magnets 41 a, 41 b extends in directions awayfrom each other in the circumferential direction from the radiallyinside toward the radially outside when viewed in the axial direction.That is, the circumferential distance between the magnet 41 a and themagnet 41 b increases from the radially inside toward the radiallyoutside.

For example, the magnet 41 a is located on one side (+θ side) in thecircumferential direction from the radially inside toward the radiallyoutside. For example, the magnet 41 b is located on the other side (−θside) in the circumferential direction from the radially inside towardthe radially outside. For example, the pair of magnets 41 a, 41 b isarranged along the V-shape expanding in the circumferential directiontoward the radially outside when viewed in the axial direction.

For example, an opening angle between the magnet 41 a and the magnet 41b disposed along the V-shape when viewed in the axial direction is anobtuse angle. For example, the magnet 41 a and the magnet 41 b aredisposed with the magnetic pole center line CL1 interposed therebetweenin the circumferential direction when viewed in the axial direction. Forexample, the magnet 41 a and the magnet 41 b are arrangedline-symmetrically with respect to the magnetic pole center line CL1when viewed in the axial direction. Hereinafter, the description of themagnet 41 b may be omitted for the same configuration as the magnet 41 aexcept that the magnet is line-symmetric with respect to the magneticpole center line CL1.

The magnet 41 a is fitted in the accommodation hole 31 a. Morespecifically, the magnet 41 a is fitted in the main body 31 c. Amongside surfaces of the magnet 41 a, a radially outer surface in thedirection orthogonal to the direction in which the main body 31 cextends is in contact with the inside surface of the main body 31 c.Among the side surfaces of the magnet 41 a, a radially inside surface inthe direction orthogonal to the direction in which the main body 31 cextends is disposed while separated radially outside from the insidesurface of the main body 31 c. For example, a gap between the radiallyinside surface in the direction orthogonal to the direction in which themain body 31 c extends in the side surfaces of the magnet 41 a and theinside surface of the main body 31 c is filled with resin.

When viewed in the axial direction, both end portions in the extendingdirection of the magnet 41 a are disposed away from both end portions inthe extending direction of the accommodation hole 31 a. When viewed inthe axial direction, the inner end 31 d and the outer end 31 e aredisposed adjacent to each other on both sides of the magnet 41 a in thedirection in which the magnet 41 a extends.

The inner end 31 d is filled with resin to form a first flux barrier 51a. The first flux barrier 51 a is a flux barrier provided on theradially inside of the magnet 41 a along the direction in which themagnet 41 a extends when viewed in the axial direction. The outer end 31e is filled with resin to form a second flux barrier 52 a. The secondflux barrier 52 a is a flux barrier provided on the radially outside ofthe magnet 41 a along the direction in which the magnet 41 a extendswhen viewed in the axial direction. That is, the rotor core 20 includesthe first flux barrier 51 a and the second flux barrier 52 a arrangedwith the magnet 41 a interposed therebetween in the direction in whichthe magnet 41 a extends when viewed in the axial direction. The rotorcore 20 includes a first flux barrier 51 b and a second flux barrier 52b arranged with the magnet 41 b interposed therebetween in the directionin which the magnet 41 b extends when viewed in the axial direction.

As described above, in the pair of accommodation holes 31 a, 31 b, thefirst flux barriers 51 a, 51 b are provided for the pair of magnets 41a, 41 b on the radially inside of the magnets 41 a, 41 b along thedirection in which the magnets 41 a, 41 b extend when viewed in theaxial direction, and the second flux barriers 52 a, 52 b are providedfor the pair of magnets 41 a, 41 b on the radially outside of themagnets 41 a, 41 b along the direction in which the magnets 41 a, 41 bextend when viewed in the axial direction. Each of the pair of firstflux barriers 51 a, 51 b and the pair of second flux barriers 52 a, 52 bis included in each magnetic pole 70.

In the description, the “direction in which the magnet extends whenviewed in the axial direction” is a direction in which a long side of arectangular magnet extends when the magnet has a rectangular shape asviewed in the axial direction, for example, like the magnets 41 a, 41 bof the example embodiment. That is, in the example embodiment, thedirection in which the magnet 41 a extends when viewed in the axialdirection is the direction in which the long side of the rectangularmagnet 41 a extends when viewed in the axial direction. The direction inwhich the magnet 41 b extends is a direction in which a long side of therectangular magnet 41 b extends when viewed in the axial direction.

In the description, the “flux barrier” is a portion capable ofpreventing the flow of magnetic flux. That is, the magnetic flux hardlypasses through each flux barrier. Each flux barrier is not particularlylimited as long as the flux barrier can prevent the flow of the magneticflux, and may include a void or a non-magnetic portion other than resin.

The magnetic pole of the magnet 41 a is disposed along the directionorthogonal to the direction in which the magnet 41 a extends when viewedin the axial direction. The magnetic pole of the magnet 41 b is disposedalong the direction orthogonal to the direction in which the magnet 41 bextends when viewed in the axial direction. The magnetic pole located onthe radially outside in the magnetic poles of the magnet 41 a and themagnetic pole located on the radially outside in the magnetic poles ofthe magnet 41 b are the same. The magnetic pole located on the radiallyinside in the magnetic poles of the magnet 41 a and the magnetic polelocated on the radially inside in the magnetic poles of the magnet 41 bare the same.

In the magnetic pole 70N, for example, the magnetic pole located on theradially outside in the magnetic poles of the magnet 41 a and themagnetic pole located on the radially outside of the magnetic poles ofthe magnet 41 b are the N pole. In the magnetic pole 70N, for example,the magnetic pole located on the radially inside of the magnetic polesof the magnet 41 a and the magnetic pole located on the radially insideof the magnetic poles of the magnet 41 b are the S pole.

Although not illustrated, in the magnetic pole 70S, the magnetic pole ofeach magnet 40 is disposed while inverted with respect to the magneticpole 70N. That is, in the magnetic pole 70S, for example, the magneticpole located on the radially outside in the magnetic poles of the magnet41 a and the magnetic pole located on the radially outside in themagnetic poles of the magnet 41 b are the S pole. In the magnetic pole70S, for example, the magnetic pole located on the radially inside inthe magnetic poles of the magnet 41 a and the magnetic pole located onthe radially inside in the magnetic poles of the magnet 41 b are the Npole.

The rotor core 20 has a plurality of third flux barriers 53 arranged atintervals in the circumferential direction. The plurality of third fluxbarriers 53 are flux barriers located radially outside the central hole21 and radially inside the accommodation hole 30. In the exampleembodiment, the third flux barrier 53 is a through-hole 32 penetratingthe rotor core 20 in the axial direction. As illustrated in FIG. 2, theplurality of third flux barriers 53 are arranged at equal intervals overthe entire circumference along the circumferential direction. Forexample, eight third flux barriers 53 are provided. The third fluxbarrier 53 may be formed by filling resin in the through-hole 32 axiallypenetrating the rotor core 20.

The circumferential position of each of the third flux barrier 53 is acircumferential position between the magnetic poles 70 adjacent to eachother in the circumferential direction. For example, the circumferentialcenter of the third flux barrier 53 is the same circumferential positionas the circumferential center between the magnetic poles 70 adjacent toeach other in the circumferential direction. The third flux barrier 53is disposed across the radially inside of the accommodation hole 31 a inone of the magnetic poles 70 adjacent to each other in thecircumferential direction and the radially inside of the accommodationhole 31 b in the other magnetic pole 70.

In the example embodiment, the third flux barrier 53 has a roundedtriangular shape convex outward in the radially direction when viewed inthe axial direction. As illustrated in FIG. 3, for example, both edgesof the third flux barrier 53 in the circumferential direction extend inparallel with the direction in which the magnet 40 accommodated in theaccommodation hole 30 located on the radially outside of each edge asviewed in the axial direction extends. For example, the radially insideedge of the third flux barrier 53 has an arc shape centered on thecenter axis J.

As illustrated in FIG. 4, the rotor core 20 is formed by laminating aplurality of plates 20 a in the axial direction. The plate 20 a is adisk shape with a plate surface oriented toward the axial direction. Forexample, the plate 20 a is an electromagnetic steel plate. The plate 20a includes a caulking portion 23 in which a part of the plate 20 a iscaulked in the axial direction. In the example embodiment, the caulkingportion 23 is a portion where a part of the plate 20 a is caulked fromthe upper side to the lower side by press working or the like. Thecaulking portion 23 protrudes downward on the lower surface of the plate20 a. By forming the caulking portion 23, a caulking recess 23 arecessed downward is provided on the upper surface of the plate 20 a.

The plate 20 a stacked adjacent to each other in the axial direction isfixed by fitting the caulking portion 23 of the plate 20 a located onthe upper side into the caulking recess 23 a of the plate 20 a locatedon the lower side. The plates 20 a stacked in this manner are fixed toeach other by the caulking portion 23 in which a part of the plate 20 ais caulked. The caulking portion 23 has higher magnetic resistance thana portion of the rotor core 20 where the caulking portion 23 is notprovided. That is, in the caulking portion 23, the magnetic flux is lesslikely to pass as compared with a portion of the rotor core 20 where thecaulking portion 23 is not provided.

As illustrated in FIG. 3, in the example embodiment, the caulkingportion 23 extends in the radial direction as viewed in the axialdirection. For example, the caulking portion 23 has a rectangular shapeelongated in the radial direction. The caulking portion 23 is located ina first region 24 between the third flux barriers 53 adjacent to eachother in the circumferential direction. The first region 24 is a regionin which the radial position is included in the radial position of thethird flux barrier 53. The first region 24 is a region surrounded byeach edge located on the side of the other third flux barrier 53 of thecircumferential edges of the pair of third flux barriers 53 adjacent toeach other in the circumferential direction, a virtual circle IC1, and avirtual circle IC2 when viewed in the axial direction.

The virtual circle IC1 is a virtual circle centered on the center axis Jand in contact with the radially outer end of the third flux barrier 53.The virtual circle IC2 is a virtual circle centered on the center axis Jand in contact with the radially inner end of the third flux barrier 53.In the example embodiment, the virtual circle IC2 overlaps an arc-shapedradially inside edge of the third flux barrier 53 when viewed in theaxial direction. In the example embodiment, the radially outer portionof the first region 24 has a circumferential dimension increasing towardthe radially outside. The first region 24 is provided between the thirdflux barriers 53 adjacent to each other in the circumferentialdirection. That is, a plurality of the first regions 24 are provided atintervals in the circumferential direction.

In the example embodiment, at least a part of the caulking portion 23 islocated radially inside the radial center of the first region 24. Theradial center of the first region 24 is located at the same radialposition as the radial center of the third flux barrier 53. The radialcenter of the first region 24 is located on a virtual circle IC3 in FIG.3. The virtual circle IC3 is a virtual circle passing through the radialcenter between the virtual circle IC1 and the virtual circle IC2. Thevirtual circle IC3 equally divides the space between the virtual circleIC1 and the virtual circle IC2 into two in the radial direction.

At least a part of the caulking portion 23 is located radially insidethe virtual circle IC3. In the example embodiment, a portion other thanthe radially outer end of the caulking portion 23 is located at theradial center of the first region 24, namely, on the radially inside ofthe virtual circle IC3. That is, in the example embodiment, the caulkingportion 23 is disposed radially inside in the first region 24.

In the specification, “the caulking portion is disposed closer to theradially inside in the first region” means that the radial center of thecaulking portion may be located on the radially inside with respect tothe radial center of the first region.

The caulking portion 23 is located radially inside the second region 25located between the radially inner ends of the pair of accommodationholes 31 a, 31 b. The second region 25 is a region betweencircumferentially inside edges of the pair of accommodation holes 31 a,31 b in the rotor core 20. The second region 25 extends in the radialdirection. The second region 25 radially connects a portion of the rotorcore 20 located radially inside the pair of accommodation holes 31 a, 31b and a portion of the rotor core 20 located radially outside the pairof accommodation holes 31 a, 31 b. For example, the circumferentialdimension of the second region 25 is uniform except for both ends in theradial direction. The radially inner end of the second region 25 has thecircumferential dimension increasing toward the radially inside. Theradially outer end of the second region 25 has the circumferentialdimension increasing toward the radially outside. The maximum dimensionin the circumferential direction of the second region 25 is smaller thanthe minimum dimension in the circumferential direction of the firstregion 24.

In the specification, “a certain object is located radially insideanother object” means that the certain object is located radially insidethe other object, and that the circumferential position of at least apart of the certain object is included in the circumferential positionof the other object. In the example embodiment, “the caulking portion 23is located radially inside the second region 25” means that the caulkingportion 23 is located radially inside the second region 25, and that thecircumferential position of at least a part of the caulking portion 23is included in the circumferential position of the second region 25. Inthe example embodiment, the entire circumferential position of thecaulking portion 23 is included in the circumferential position of thesecond region 25.

The maximum dimension in the circumferential direction of the caulkingportion 23 is smaller than the minimum dimension in the circumferentialdirection of the second region 25. The caulking portion 23 is disposedon an extension line on the radially inside of the second region 25. Thecaulking portion 23 is disposed on the magnetic pole center line CL1when viewed in the axial direction. The magnetic pole center line CL1passes through the circumferential center of the caulking portion 23when viewed in the axial direction.

In the example embodiment, at least a part of the caulking portion 23 islocated between a first virtual line IL1 a that is parallel with adirection in which one accommodation hole 31 a of the pair ofaccommodation holes 31 a, 31 b and is along a radially inside edge ofone accommodation hole 31 a extends and a second virtual line IL1 b inparallel with the first virtual line IL1 a and in contact with an edgeof the third flux barrier 53 from the radially outside when viewed inthe axial direction. The first virtual line IL1 a extends along theradially inside edge of the main body 31 c of the accommodation hole 31a when viewed in the axial direction. The first virtual line IL1 aoverlaps the radially inside edge of the main body 31 c when viewed inthe axial direction. The second virtual line IL1 b extends along acircumferentially inside (−θ side) edge of the third flux barrier 53located radially inside the accommodation hole 31 a when viewed in theaxial direction, and overlaps the edge. In the example embodiment, theentire caulking portion 23 is located between the first virtual line IL1a and the second virtual line IL1 b in the radial direction.

In the example embodiment, at least a part of the caulking portion 23 islocated radially inside a third virtual line IL1 c that extends inparallel with the first virtual line IL1 a and the second virtual lineIL1 b and bisects the first virtual line IL1 a and the second virtualline IL1 b as viewed in the axial direction. In the example embodiment,the entire caulking portion 23 is located radially inside the thirdvirtual line IL1 c. In the example embodiment, the entire caulkingportion 23 is located between the second virtual line IL1 b and thethird virtual line IL1 c in the radial direction.

The first virtual line IL2 a, the second virtual line IL2 b, and thethird virtual line IL2 c in FIG. 3 are provided similarly to the firstvirtual line IL1 a, the second virtual line IL1 b, and the third virtualline IL1 c except that the first virtual line IL2 a, the second virtualline IL2 b, and the third virtual line IL2 c are line-symmetric with themagnetic pole center line CL1 interposed therebetween with respect tothe other accommodation hole 31 b of the pair of accommodation holes 31a, 31 b and the third flux barrier 53 located radially inside theaccommodation hole 31 b. The disposition relationship of the caulkingportion 23 with respect to the first virtual line IL2 a, the secondvirtual line IL2 b, and the third virtual line IL2 c is similar to thedisposition relationship of the caulking portion 23 with respect to thefirst virtual line IL1 a, the second virtual line IL1 b, and the thirdvirtual line IL1 c except that the disposition relationship isline-symmetric with respect to the magnetic pole center line CL1.

A plurality of caulking portions 23 are provided for each plate 20 a. Ineach plate 20 a, the plurality of caulking portions 23 are arranged atequal intervals over the entire circumference along the circumferentialdirection. One caulking portion 23 is provided for each of the pluralityof first regions 24.

In the example embodiment, the caulking portion 23 includes the caulkingportion 23 located on the radially outside of the protrusion 22. Asillustrated in FIG. 2, in the example embodiment, one caulking portion23 is provided on the radially outside of each of the two protrusions 22provided with the center axis J interposed therebetween in the radialdirection.

In the specification, “a certain object is located on the radiallyoutside of another object” means that the certain object is located onthe radially outside of the other object, and that the circumferentialposition of at least a part of the certain object may be included in thecircumferential position of the other object. That is, in the exampleembodiment, “the caulking portion 23 is located on the radially outsideof the protrusion 22” means that the caulking portion 23 is located onthe radially outside of the protrusion 22, and that the circumferentialposition of at least a part of the caulking portion 23 is included inthe circumferential position of the second region 25. In the exampleembodiment, the entire circumferential position of the caulking portion23 is included in the circumferential position of the protrusion 22. Forexample, the circumferential center of the caulking portion 23 and thecircumferential center of the protrusion 22 have the samecircumferential position.

As illustrated in FIG. 5, the rotor core 20 has a first gap 26 locatedbetween the magnetic poles 70N, 70S adjacent to each other in thecircumferential direction. A plurality of first gaps 26 are providedalong the circumferential direction. The first gap 26 iscircumferentially sandwiched between the second flux barriers 52 a, 52 bincluded in the magnetic poles 70N, 70S adjacent to each other in thecircumferential direction. In the example of FIG. 5, the first gap 26 iscircumferentially sandwiched between the second flux barrier 52 b of themagnetic pole 70N and the second flux barrier 52 a of the magnetic pole70S adjacent on the other side (−θ side) in the circumferentialdirection of the magnetic pole 70N. The first gap 26 extends in theradial direction.

The first gap 26 has a widened portion 26 i in which the circumferentialdimension increases toward the radially outside. In the exampleembodiment, the widened portion 26 i is a radially outer portion of thefirst gap 26. The radially outer end of the widened portion 26 i isconnected to second gaps 27 a, 27 b located between the outer peripheralsurface of the rotor core 20 and the second flux barriers 52 a, 52 b inthe radial direction.

The second gap 27 a is located between the outer peripheral surface ofthe rotor core 20 and the second flux barrier 52 b in the radialdirection, and is connected to an end on one side (+θ side) in thecircumferential direction at the radially outer end of the widenedportion 26 i. The second gap 27 a is positioned between a core recess 29e (described later) and the second flux barrier 52 b in the radialdirection. The second gap 27 b is located between the outer peripheralsurface of the rotor core 20 and the second flux barrier 52 a in theradial direction, and is connected to an end on the other side (−0 side)in the circumferential direction at the radially outer end of thewidened portion 26 i. The second gap 27 b is positioned between the corerecess 29 f and the second flux barrier 52 a described later in theradial direction. The second gaps 27 a, 27 b extend in thecircumferential direction. The second gaps 27 a, 27 b connect the firstgap 26 and a portion located on the radially outer side of the pair ofmagnets 41 a, 41 b in the circumferential direction.

Edges 26 a, 26 b on both sides in the circumferential direction of thefirst gap 26 include straight portions 26 c, 26 f, outside connectingportions 26 d, 26 g, and inside connecting portions 26 e, 26 h whenviewed in the axial direction. The edge 26 a on one circumferentialdirection side (+θ side) of the first gap 26 is constructed with thestraight portion 26 c, the outside connecting portion 26 d, and theinside connecting portion 26 e. The edge 26 b on the othercircumferential direction side (−θ side) of the first gap 26 isconstructed with the straight portion 26 f, the outside connectingportion 26 g, and the inside connecting portion 26 h.

The straight portion 26 c linearly extends in a directioncircumferentially away from the other edge 26 b of the edges 26 a, 26 bon both sides in the circumferential direction of the first gap 26toward the radially outside when viewed in the axial direction. Thestraight portion 26 c is constructed with a part of the circumferentialedge portion of the widened portion 26 i. The outside connecting portion26 d is bent in a direction (+θ direction) away from the radially outerend of the straight portion 26 c with respect to the other edge 26 bwhen viewed in the axial direction, and is connected to the radiallyinside edge of the second gap 27 a. In the example embodiment, theoutside connecting portion 26 d has an arc shape when viewed in theaxial direction.

The inside connecting portion 26 e is bent in a direction away from theother edge 26 b from the radially inner end of the straight portion 26c, and is connected to the radially inside edge of the accommodationhole 31 b. A shape of the inside connecting portion 26 e differsdepending on the plate 20 a. Specifically, the plate 20 a includes theplate 20 a in which the support 28 a is provided in a portionconstituting the inside connecting portion 26 e and the plate 20 a inwhich the support 28 a is not provided in the portion constituting theinside connecting portion 26 e. In the example embodiment, these twotypes of plates 20 a are alternately stacked along the axial direction.The support 28 a is a portion protruding to the inside of theaccommodation hole 31 b. The support 28 a supports the magnet 41 b fromthe radially outside along the direction in which the magnet 41 bextends when viewed in the axial direction. As described above, in theexample embodiment, the inside connecting portion 26 e includes thesupport 28 a that protrudes to the inside of the accommodation hole 31 band supports the magnet 41 b. For example, a part of the support 28 a isprovided on the straight portion 26 c. In each of the above two types ofthe plates 20 a, a plurality of stacked bodies may be alternatelystacked. That is, the stacked body in which the plurality of plates 20 aprovided with the support 28 a are stacked and the stacked body in whichthe plurality of plates 20 a not provided with the support 28 a arestacked may be stacked along the axial direction.

At this point, in the example embodiment, the inner end 31 g is providedwith a support 28 b that protrudes inside the accommodation hole 31 band supports the magnet 41 b. The support 28 b supports the magnet 41 bfrom the radially inside along the direction in which the magnet 41 bextends when viewed in the axial direction. Thus, the magnet 41 b issupported by the pair of supports 28 a, 28 b from both sides in thedirection in which the magnet 41 b extends when viewed in the axialdirection. The same applies to the magnet 41 a.

A portion of the inside connecting portion 26 e where the support 28 ais not provided has an arc shape when viewed in the axial direction. Acurvature radius of the inside connecting portion 26 e is smaller than acurvature radius of the outside connecting portion 26 d. In other words,the curvature radius of the outside connecting portion 26 d is largerthan the curvature radius of the inside connecting portion 26 e. Thus,in the example embodiment, the outside connecting portion 26 d is longerthan the inside connecting portion 26 e when viewed in the axialdirection.

The straight portion 26 f provided at the edge 26 b is providedline-symmetrically across a center line CL2 extending in the radialdirection through the center axis J and the circumferential center ofthe first gap 26 with respect to the straight portion 26 c. The outsideconnecting portion 26 g provided at the edge 26 b is providedline-symmetrically across the center line CL2 with respect to theoutside connecting portion 26 d. The inside connecting portion 26 hprovided at the edge 26 b is provided substantially line-symmetricallyacross the center line CL2 with respect to the inside connecting portion26 e. In the plate 20 a illustrated in the example of FIG. 5, thesupport 28 a is provided in the inside connecting portion 26 e, whereasthe support 28 a is not provided in the inside connecting portion 26 h.

The radially outside surface of the rotor core 20 includes core recesses29 e, 29 f recessed radially inside and a core protrusion 29 dprotruding radially outside. The core recesses 29 e, 29 f are providedin respective portions located radially outside the pair of second fluxbarriers 52 a, 52 b sandwiching the first gap 26 in the circumferentialdirection. The core recess 29 e is located radially outside the secondflux barrier 52 b. The core recess 29 f is located radially outside thesecond flux barrier 52 a. The core protrusion 29 d is located betweenthe pair of core recesses 29 e, 29 f located radially outside the pairof second flux barriers 52 a, 52 b in the circumferential direction. Forexample the core recesses 29 e, 29 f and the core protrusion 29 d areprovided over the entire rotor core 20 in the axial direction.

The core recesses 29 e, 29 f extend in the circumferential direction. Inthe example embodiment, the radial positions of the core recesses 29 e,29 f become the radially innermost side in a portion adjacent to thecore protrusion 29 d in the circumferential direction, and become theradially outside as being circumferentially separated from the portionlocated on the radially innermost side with respect to the coreprotrusion 29 d. The inner edge shapes of the core recesses 29 e, 29 fextend in a curved shape when viewed in the axial direction. The pair ofcore recesses 29 e, 29 f provided with the core protrusion 29 dsandwiched therebetween in the circumferential direction has aline-symmetrical shape with respect to the center line CL2 when viewedin the axial direction. For this reason, in the following description,only the core recess 29 e located on one side (+e side) in thecircumferential direction as a representative of the pair of corerecesses 29 e, 29 f may be described.

In the example embodiment, a portion of the core recess 29 e located onthe radially innermost side is located between a second virtual line IL4a, which passes through the center axis J and is in contact with theedge 26 a on one side (+θ side) in the circumferential direction of thefirst gap 26, and a third virtual line IL4 b, which sandwiches thesecond flux barrier 52 b in the circumferential direction with thesecond virtual line IL4 a to pass through the center axis J and is incontact with the edge of the second flux barrier 52 b, when viewed inthe axial direction. In the example embodiment, the third virtual lineIL4 b passes through a corner located on the other side (−θ side) in thecircumferential direction and on the radially outside of the corner ofthe magnet 41 b when viewed in the axial direction.

In the example embodiment, a portion of the core recess 29 e located onthe radially innermost side is located closer to the core protrusion 29d adjacent to the core recess 29 e with respect to a fourth virtual lineIL4 c that passes through the center axis J and bisects the secondvirtual line IL4 a and the third virtual line IL4 b in thecircumferential direction when viewed in the axial direction. In theexample embodiment, the portion of the core recess 29 e located on theradially innermost side is located on the other side (−0 side) in thecircumferential direction with respect to the fourth virtual line IL4 c.

In the example embodiment, when viewed in the axial direction, acircumferential distance between the portions where the pair of firstvirtual lines IL3 a, IL3 b extending while overlapping the respectivestraight portions 26 c, 26 f provided at the edges 26 a, 26 b on bothsides in the circumferential direction of the first gap 26 intersect theradially outside surface of the rotor core 20 is the same as thecircumferential dimension in the radially outside surface of the coreprotrusion 29 d. When viewed in the axial direction, the first virtualline IL3 a extends along the straight portion 26 c, and passes throughan end on one side (+θ side) in the circumferential direction in theradially outside surface of the core protrusion 29 d. When viewed in theaxial direction, the first virtual line IL3 b extends along the straightportion 26 f, and passes through an end on the other side (−θ side) inthe circumferential direction in the radially outside surface of thecore protrusion 29 d.

The edges on both sides in the circumferential direction of the coreprotrusion 29 d include connecting portions 29 c connected to theradially outside edges of the second gaps 27 a, 27 b. The connectingportion 29 c constitutes a part of the edges of the core recesses 29 e,29 f. In the example embodiment, the connecting portion 29 c has an arcshape recessed radially inside when viewed in the axial direction. Thecurvature radius of the connecting portion 29 c is smaller than thecurvature radius of the outside connecting portion 26 d. In other words,the curvature radius of the outside connecting portion 26 d is largerthan the curvature radius of the connecting portion 29 c. Accordingly,the outside connecting portion 26 d is longer than the connectingportion 29 c when viewed in the axial direction.

The plurality of core protrusions 29 d and the plurality of corerecesses 29 e, 29 f are provided along the circumferential direction.The core protrusion 29 d and the pair of core recesses 29 e, 29 f areprovided for each first gap 26.

Because the core recesses 29 e, 29 f and the core protrusion 29 d areprovided, the radially outside surface of the rotor core 20 has a shapeincluding a first circular arc 29 a and a second circular arc 29 b whenviewed in the axial direction. The first circular arc 29 a is a radiallyoutside surface of a portion having the maximum radius of the rotor core20. The first circular arc 29 a extends in an arcuate shape centered onthe center axis J when viewed in the axial direction. In the exampleembodiment, the first circular arc 29 a is formed by the radiallyoutside surface of the core protrusion 29 d.

The second circular arc 29 b extends in an arcuate shape having acurvature radius different from that of the first circular arc 29 a whenviewed in the axial direction. The curvature radius of the secondcircular arc 29 b is smaller than the curvature radius of the firstcircular arc 29 a. The magnetic pole center line CL1 passes through thecircumferential center of the second circular arc 29 b when viewed inthe axial direction. The radial position at the circumferential centerof the second circular arc 29 b is the same as the radial position ofthe first circular arc 29 a. That is, the radius of the rotor core 20becomes the maximum even in the circumferential center of the secondcircular arc 29 b.

A plurality of first circular arcs 29 a and a plurality of secondcircular arcs 29 b are provided. The first circular arc 29 a and thesecond circular arc 29 b are alternately provided along thecircumferential direction. In the example embodiment, the core recesses29 e, 29 f are provided at both circumferential ends of the secondcircular arc 29 b, respectively.

As illustrated in FIG. 6, magnetic fluxes MF1, MF3, which pass from thestator 60 through the rotor core 20 and return to the stator 60 again,are generated are generated when power is supplied to the stator 60. Themagnetic flux MF1 is a magnetic flux passing between the pair of magnets41 a, 41 b and the third flux barrier 53 in the radial direction. Themagnetic flux MF1 flows into the rotor core 20 from the first circulararc 29 a, and flows in a curved shape protruding radially inside betweenthe pair of magnets 41 a, 41 b and the third flux barrier 53 in theradial direction. The magnetic flux MF1 flowing between the pair ofmagnets 41 a, 41 b and the third flux barrier 53 in the radial directionflows out of the rotor core 20 from the first circular arc 29 a adjacentto the first circular arc 29 a with the second circular arc 29 binterposed therebetween, and returns to the stator 60. The magnetic fluxMF3 flows into the rotor core 20 from the second circular arc 29 b,passes through the second gaps 27 a, 27 b, and returns to the stator 60from the first circular arc 29 a.

In addition, the magnet 40 generates a magnetic flux MF2 flowing betweenthe rotor core 20 and the stator 60. The magnetic flux MF2 passesthrough the magnets 41 a, 41 b, which are provided in the differentmagnetic poles 70 and disposed adjacent to each other at intervals inthe circumferential direction in the radial direction. The magnetic fluxMF2 flows in the rotor core 20 in a curved shape protruding inside inthe radial direction. In the example of FIG. 6, the magnetic flux MF2flows out of the rotor core 20 from the second circular arc 29 b, andflows to the stator 60.

According to the example embodiment, the caulking portion 23 is locatedin the first region 24 between the through-holes 32 adjacent to eachother in the circumferential direction. At this point, the through-hole32 (third flux barrier 53) is a portion through which a magnetic fluxhardly passes. For this reason, the first region 24 between thethrough-holes 32 in the circumferential direction hardly become amagnetic path through which the magnetic flux passes. Thus, when beingprovided in the first region 24, the caulking portion 23 hardlyobstructs the magnetic flux flowing in the rotor core 20. Specifically,when the caulking portion 23 is provided in the first region 24, themagnetic flux MF1 in FIG. 6 can be prevented from being obstructed bythe caulking portion 23. In addition, the caulking portion 23 having arelatively high magnetic resistance can prevent the magnetic flux MF1from leaking radially inside from between the through-holes 32. Thus,the decrease in magnetic efficiency of the rotary electric machine 1 canbe prevented.

For example, the portion where the through-hole 32 (third flux barrier53) is made tends to have a mass smaller than that of other portions ofthe rotor core 20 by making a hole penetrating the rotor core 20 in theaxial direction. For this reason, weight of the rotor core 20 can bereduced by providing the through-hole 32.

For example, in the portion where the through-hole 32 (third fluxbarrier 53) is made rigidity tends to be lowered because thethrough-hole 32 penetrating the rotor core 20 in the axial direction ismade. On the other hand, the rigidity tends to be higher than that ofother portions of the rotor core 20 because a part of the caulkingportion 23 is caulked in the axial direction. For this reason, a portionof the rotor core 20 where the rigidity is likely to decrease can bereinforced by providing the caulking portion 23 in the first region 24between the through-holes 32.

When the rotor 10 rotates, stress in the circumferential directioneasily occurs in the first region 24. In particular, when the rigidityof the rotor core 20 decreases in a periphery of the first region 24 bymaking the through-hole 32 axially penetrating the rotor core 20 as inthe example embodiment, torsional stress in the circumferentialdirection easily occurs in the first region 24. On the other hand,because a portion of the rotor core 20 where the rigidity is likely todecrease by providing the caulking portion 23 in the first region 24,deformation or the like of the first region 24 can be prevented evenwhen the stress in the circumferential direction is generated.

In addition, the first region 24 between the through-holes 32 (thirdflux barrier 53) is a relatively wide region that can be easily securedin the rotor core 20. For this reason, suitably the caulking portion 23is easily provided in the first region 24. Thus, the plates 20 a can besuitably fixed to each other by the caulking portion 23.

According to the example embodiment, at least a part of the caulkingportion 23 is located radially inside the radial center of the firstregion 24. For this reason, the caulking portion 23 can be easilydisposed radially inside, and the caulking portion 23 can more hardlyobstruct the magnetic flux MF1. Thus, the decrease in the magneticefficiency of the rotary electric machine 1 can be further prevented.

According to the example embodiment, the caulking portion 23 is disposedradially inside in the first region 24. For this reason, the caulkingportion 23 can more hardly obstruct the magnetic flux MF1. Thus, thedecrease in the magnetic efficiency of the rotary electric machine 1 canbe further prevented.

According to the example embodiment, the caulking portion 23 extends inthe radial direction when viewed in the axial direction. For thisreason, the circumferential dimension of the caulking portion 23 iseasily relatively reduced. Thus, the interval between the through-holes32 is easily reduced while the interval between the caulking portion 23and the through-hole 32 (third flux barrier 53) is ensured in thecircumferential direction. Consequently, the through-hole 32 is easilyenlarged while strength is secured in the first region 24. For thisreason, the magnetic flux MF1 can be prevented from leaking radiallyinside from between the through-holes 32 while the strength of the rotorcore 20 is secured. For this reason, the decrease in the magneticefficiency of the rotary electric machine 1 can be further prevented. Inaddition, the weight of the rotor core 20 can be further reduced becausethe through-hole 32 is enlarged.

According to the example embodiment, the caulking portion 23 is locatedradially inside a second region 25 located between the radially innerends of the pair of accommodation holes 31 a, 31 b. The second region 25tends to be relatively narrow, and the rigidity tends to be relativelysmall. For this reason, the rigidity of the second region 25 can beeasily reinforced by providing the caulking portion 23 on the radiallyinside of the second region 25. The plates 20 a can be suitably fixed toeach other by the caulking portion 23 because the caulking portion 23 isdisposed while avoiding the relatively narrow second region 25.

According to the example embodiment, when viewed in the axial direction,at least a part of the caulking portion 23 is located between the firstvirtual line IL1 a along the radially inside edge of the accommodationholes 31 a in parallel with the direction in which the accommodationhole 31 a in the pair of accommodation holes 31 a, 31 b extends and thesecond virtual line IL1 b that is in parallel with the first virtualline IL1 a and in contact with the edge of the through-hole 32 (thirdflux barrier 53) from the radially outside. For this reason, thecaulking portion 23 can more hardly obstruct the magnetic flux MF1.Thus, the decrease in the magnetic efficiency of the rotary electricmachine 1 can be further prevented.

According to the example embodiment, at least a part of the caulkingportion 23 is located radially inside the third virtual line IL1 c thatextends in parallel with the first virtual line IL1 a and the secondvirtual line IL1 b and bisects the first virtual line IL1 a and thesecond virtual line IL1 b when viewed in the axial direction. For thisreason, the caulking portion 23 can be more easily disposed on theradially inside, and the caulking portion 23 can more hardly obstructthe magnetic flux MF1. Thus, the decrease in the magnetic efficiency ofthe rotary electric machine 1 can be further prevented.

According to the example embodiment, the caulking portion 23 is providedfor each of the plurality of first regions 24. For this reason, theplates 20 a can be more firmly fixed to each other.

According to the example embodiment, the caulking portion 23 includesthe caulking portion 23 located on the radially outside of theprotrusion 22. For this reason, even when the stress in thecircumferential direction is applied to the portion where the protrusion22 is provided during the rotation of the rotor 10, peeling of theplates 20 a from each other is easily prevented by the caulking portion23 located on the radially outside of the protrusion 22. Even when theprotrusion 22 is press-fitted into the recess 11 a, the peeling of theplates 20 a from each other is easily prevented during the press-fittingof the protrusion 22.

According to the example embodiment, because the core recesses 29 e, 29f are provided, the magnetic flux flowing between the portion where thecore recesses 29 e, 29 f are provided and the stator 60 in the radialdirection can be decreased. Thus, suitably the magnetic flux MF3 in FIG.6 can be easily flown. Consequently, the generation of the unnecessaryflow of the magnetic flux can be prevented between the rotor core 20 andthe stator 60, and a torque ripple can be reduced.

In addition, according to the example embodiment, the first gap 26includes the widened portion 26 i in which the circumferential dimensionincreases toward the radially outside. The radially outer end of thewidened portion 26 i is connected to the second gaps 27 a, 27 b locatedbetween the core recesses 29 e, 29 f and the second flux barriers 52 a,52 b in the radial direction. For this reason, the circumferential widthof the radially outer end of the widened portion 26 i connected to thesecond gaps 27 a, 27 b can be relatively large, and the stress can beeasily dispersed in the widened portion 26 i. Thus, concentration of thestress on the second gaps 27 a, 27 b can be prevented. Consequently, thedeformation and damage of the second gaps 27 a, 27 b can be preventedwhile the torque ripple is reduced by providing the core recesses 29 e,29 f. In this way, according to the example embodiment, the rigidity ofthe rotor core 20 can be improved. In addition, the magnetic flux caneasily flow through the first gap 26 because the circumferential widthof the widened portion 26 i can be made relatively large. Specifically,suitably the magnetic flux MF1 in FIG. 6 can easily flow. Thus, themagnetic efficiency of the rotary electric machine 1 can be improved.

According to the example embodiment, the outside connecting portions 26d, 26 g are longer than the inside connecting portions 26 e, 26 h whenviewed in the axial direction. For this reason, the stress can be moreeasily dispersed in the outside connecting portions 26 d, 26 g than inthe inside connecting portions 26 e, 26 h. Thus, the concentration ofthe stress on the second gaps 27 a, 27 b can further prevented. Inaddition, the circumferential dimension of the first gap 26 can be moreeasily increased in the outside connecting portions 26 d, 26 g than inthe inside connecting portions 26 e, 26 h. Thus, the rigidity of therotor core 20 is easily increased in the radially outside where thegenerated stress tends to increase. Consequently, the rigidity of therotor core 20 can be further improved.

In addition, according to the example embodiment, the inside connectingportions 26 e, 26 h include the support 28 a that protrudes to theinside of the accommodation hole 30 to support the magnet 40. For thisreason, the circumferential dimension of the first gap 26 can beincreased in the portion where the support 28 a is provided in theinside connecting portions 26 e, 26 h. For this reason, the rigidity ofthe radially inside of the first gap 26 can be improved. Consequently,the rigidity of the rotor core 20 can be further improved.

According to the example embodiment, when viewed in the axial direction,the circumferential distance between the portions where the pair offirst virtual lines IL3 a, IL3 b extending while overlapping therespective straight portions 26 c, 26 f provided at the edges 24 a, 24 bon both sides in the circumferential direction of the first gap 26intersect the radially outside surface of the rotor core 20 is the sameas the circumferential dimension of the radially outside surface of thecore protrusion 29 d. For this reason, the magnetic flux MF1 passingthrough the radially outside surface of the core protrusion 29 d,namely, the first circular arc 29 a can sufficiently flow to the firstgap 26. Thus, the magnetic efficiency of the rotary electric machine 1can be improved.

In addition, according to the example embodiment, the edges on bothsides in the circumferential direction of the core protrusion 29 dinclude the connecting portion 29 c connected to the radially outsideedges of the second gaps 27 a, 27 b. The outside connecting portions 26d, 26 g are longer than the connecting portion 29 c when viewed in theaxial direction. For this reason, the stress can be more easilydispersed in the outside connecting portions 26 d, 26 g. Thus, theconcentration of the stress on the second gaps 27 a, 27 b can furtherprevented.

According to the example embodiment, the radially outside surface of therotor core 20 includes the first circular arc 29 a and the secondcircular arc 29 b. The core recesses 29 e, 29 f are provided at bothends in the circumferential direction of the second circular arc 29 b.With such the shape, the magnetic flux MF3 in FIG. 6 can more suitablyflow. Thus, the torque ripple can be further reduced.

According to the example embodiment, the portion of the core recess 29 elocated on the radially innermost side is located between the secondvirtual line IL4 a, which passes through the center axis J and is incontact with the edge 26 a on one side in the circumferential directionof the first gap 26, and the third virtual line IL4 b, which sandwichesthe second flux barrier 52 b in the circumferential direction with thesecond virtual line IL4 a to pass through the center axis J and is incontact with the edge of the second flux barrier 52 b, when viewed inthe axial direction. For this reason, the second gap 27 a located on theradially outside of the second flux barrier 52 b can be easily separatedradially inside from the stator 60, and the magnetic flux MF3 can beprevented from leaking radially outside from the second gap 27 a. Thus,the torque ripple can be further reduced.

According to the example embodiment, the portion of the core recess 29 elocated on the radially innermost side is located closer to the coreprotrusion 29 d adjacent to the core recess 29 e than the fourth virtualline IL4 c that passes through the center axis J to bisect the secondvirtual line IL4 a and the third virtual line IL4 b in thecircumferential direction when viewed in the axial direction. Thus, themagnetic flux MF3 hardly leak radially outward at a portion adjacent tothe core protrusion 29 d in the circumferential direction. Consequently,the torque ripple can be more suitably reduced.

The present disclosure is not limited to the above-described exampleembodiment, and other structures may be adopted in other preferredexample embodiments of the present disclosure within the scope of thetechnical idea of the present disclosure. The caulking portion may bedisposed at any position as long as the caulking portion is located inthe first region between the through-holes (third flux barriers 53)adjacent to each other in the circumferential direction. The shape ofthe caulking portion is not particularly limited. The caulking portionmay have a circular shape or a polygonal shape other than a quadrangularshape when viewed in the axial direction.

Like the caulking portion 123 of the rotor core 120 in FIG. 7, thecaulking portion may extend in a direction intersecting the radialdirection when viewed in the axial direction. According to thisconfiguration, the circumferential dimension of the caulking portion 123can be relatively increased. For this reason, the caulking portion 123having the relatively high magnetic resistance can prevent the magneticflux MF1 from leaking radially inside from between the through-holes 32(third flux barrier 53). In addition, the caulking portion 123 can befurther prevented from obstructing the flow of the magnetic flux MF1because the radial dimension of the caulking portion 123 is maderelatively small. Thus, the decrease in the magnetic efficiency of therotary electric machine can be further prevented. For example, thecaulking portion 123 has a rectangular shape extending in thecircumferential direction orthogonal to the radial direction in whichthe magnetic pole center line CL1 extends. The entire caulking portion123 is located radially inside the virtual circle IC3.

The plurality of through-holes (third flux barriers 53) disposed atintervals in the circumferential direction may have any shape. Theplurality of through-holes may have a polygonal shape of a square ormore, a circular shape, or an elliptical shape when viewed in the axialdirection.

The first gap may have any shape as long as the first gap has thewidened portion. In the first gap, the outside connecting portion andthe inside connecting portion may be linear when viewed in the axialdirection. The first gap may not have the widened portion. When viewedin the axial direction, the circumferential distance between portionswhere a pair of virtual lines (first virtual lines IL3 a, IL3 b)extending while overlapping each of the straight portions provided atthe edges on both sides in the circumferential direction of the firstgap intersects the radially outside surface of the rotor core may belarger than the circumferential dimension of the radially outsidesurface of the core protrusion. The core protrusion and the core recessmay not be provided.

At least three magnets may be disposed in each magnetic pole. Forexample, the magnet, which is located radially outside the magnets 41 a,41 b and extending in the direction orthogonal to the radial directionwhen viewed in the axial direction, may be arranged in each magneticpole in addition to the pair of magnets 41 a, 41 b of theabove-described example embodiment. In this case, in each magnetic pole,three magnets are arranged along a V shape when viewed in the axialdirection. Furthermore, a pair of magnets, which is located on theradially outsides of the magnets 41 a, 41 b and extends in directionsaway from each other in the circumferential direction from the radiallyinside toward the radially outside when viewed in the axial directionmay be further disposed in addition to the magnets 41 a, 41 b. That is,two pairs of magnets arranged along the V-shape expanding in thecircumferential direction toward the radially outside may be arrangedside by side in the radial direction.

The protrusion and the recess provided in the shaft and the central holemay be provided opposite to those in the above-described exampleembodiment. That is, the central hole may have a recess, and the shaftmay have a protrusion fitted into the recess. The recess and theprotrusion may not be provided.

The rotary electric machine applied to the present disclosure is notlimited to the motor, and may be a generator. An application of therotary electric machine is not limited. For example, the rotaryelectrical machine may be mounted on a vehicle or a device other thanthe vehicle. Features as described above in the specification may beappropriately combined as long as no conflict arises.

Features of the above-described example embodiments and themodifications thereof may be combined appropriately as long as noconflict arises.

While example embodiments of the present disclosure have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present disclosure. The scope of the presentdisclosure, therefore, is to be determined solely by the followingclaims.

What is claimed is:
 1. A rotor rotatable about a center axis extendingin an axial direction, the rotor comprising: a shaft extending in theaxial direction; a rotor core including a central hole through which theshaft passes and accommodation holes located radially outside thecentral hole, the rotor core being fixed to the shaft; and magnetsaccommodated in the accommodation holes; wherein the accommodation holesinclude a pair of accommodation holes arranged at intervals in acircumferential direction; the pair of accommodation holes extends in adirection away from each other in the circumferential direction from aradially inside toward a radially outside when viewed in the axialdirection; the magnets includes a pair of magnets accommodated in thepair of accommodation holes; the pair of magnets extends in thedirection away from each other in the circumferential direction from theradially inside toward the radially outside when viewed in the axialdirection; the rotor core includes through-holes at intervals in thecircumferential direction and plates laminated in the axial direction;the through-holes are located radially outside the central hole andradially inside the accommodation hole; the stacked plates are fixed toeach other by a caulking portion in which a portion of the plates iscaulked; and the caulking portion is located in a first region betweenthe through-holes adjacent to each other in the circumferentialdirection.
 2. The rotor according to claim 1, wherein at least a portionof the caulking portion is located radially inside a radial center ofthe first region.
 3. The rotor according to claim 1, wherein thecaulking portion is radially inside in the first region.
 4. The rotoraccording to claim 1, wherein the caulking portion extends in a radialdirection when viewed in the axial direction.
 5. The rotor according toclaim 1, wherein the caulking portion extends in a directionintersecting a radial direction when viewed in the axial direction. 6.The rotor according to claim 1, wherein the caulking portion is locatedradially inside a second region located between radially inner ends ofthe pair of accommodation holes.
 7. The rotor according to claim 1,wherein at least a portion of the caulking portion is located between afirst virtual line, which is in parallel with a direction in which oneof the pair of accommodation holes extends, and which extends along aradially inside edge of the one accommodation hole, and a second virtualline, which is in parallel with the first virtual line and in contactwith the edge of the through-hole from the radially outside when viewedin the axial direction.
 8. The rotor according to claim 7, wherein atleast a portion of the caulking portion is located radially inside athird virtual line, which extends in parallel with the first virtualline and the second virtual line and bisects a portion between the firstvirtual line and the second virtual line when viewed in the axialdirection.
 9. The rotor according to claim 1, wherein a plurality of thefirst regions is provided at intervals in the circumferential direction;and the caulking portion is provided for each of the plurality of firstregions.
 10. The rotor according to claim 1, wherein one of the shaftand the central hole includes a recess recessed in the radial direction;another one of the shaft and the central hole includes a protrusion thatprotrudes in a radial direction and is fitted into the recess; and thecaulking portion is located radially outside the protrusion.
 11. Arotary electric machine comprising: the rotor according to claim 1; anda stator located on a radially outside of the rotor.